Process for deinking wastepaper with organically modified smectite clay

Abstract

A process for deinking wastepaper with an aqueous system, which includes: (a) contacting wastepaper with an aqueous system which contains an agent of one or more organically modified smectite-type clays; and (b) recovering deinked paper pulp from the aqueous system.

What is claimed is: 
     
       1. A process for deinking wastepaper, which comprises: (a) contacting wastepaper with an aqueous system which contains an agent in an amount effective to deink the wastepaper, wherein the agent comprises: one or more organically modified smectite-type clays; and   (b) recovering deinked paper pulp from the aqueous system.   
     
     
       2. The process of claim 1, wherein said agent is present in an amount of from about 0.05% to about 50% by weight, based on the dry weight of said wastepaper. 
     
     
       3. The process of claim 1, wherein said wastepaper is selected from the group consisting of newspaper, magazines, computer paper, legal documents and book stock. 
     
     
       4. The process of claim 1, wherein said wastepaper contains a water-based or an oil-based ink. 
     
     
       5. The process of claim 1, wherein the recovering step includes air sparging in order to float ink removed from the wastepaper to the surface of the aqueous system. 
     
     
       6. The process of claim 1, wherein said organically modified smectite-type clay comprises the reaction product of: (a) a smectite-type clay having a cation exchange capacity of at least 50 milliequivalents per 100 grams of clay; and   (b) one or more quaternary ammonium salts in an amount of from about 40% to about 200% of the cation exchange capacity of the smectite-type clay.   
     
     
       7. The process of claim 6, wherein said smectite-type clay is sheared prior to reaction with said quaternary ammonium salt. 
     
     
       8. The process of claim 1, wherein said organically modified smectite-type clay is in aqueous slurry form prior to addition to the aqueous system. 
     
     
       9. The process of claim 1, wherein said organically modified smectite-type clay is in dry powdered form prior to addition to the aqueous system. 
     
     
       10. The process of claim 1, wherein said wastepaper contains tacky contaminants. 
     
     
       11. The process of claim 1, wherein said agent comprises a mixture of at least one hydrophobic organically modified clay with at least one hydrophilic organically modified clay. 
     
     
       12. The process of claim 1, wherein said agent comprises an organically modified clay formed with a quaternary ammonium salt having both hydrophobic and hydrophilic groups. 
     
     
       13. The process of claim 1, wherein the recovery step includes floatation of ink removed from the wastepaper to the surface of the aqueous system. 
     
     
       14. The process of claim 13, wherein said agent comprises a reaction product of crude hectorite clay and methyl trihydrogenated tallow ammonium chloride. 
     
     
       15. The process of claim 1, wherein the recovery step includes water washing the deinked paper pulp. 
     
     
       16. The process of claim 15, wherein said agent comprises a reaction product of crude hectorite clay and octadecyl-methyl-ammonium chloride. 
     
     
       17. The process of claim 1, wherein said organically modified smectite-type clay is the reaction product of (a) a smectite-type clay selected from the group consisting of crude hectorite, crude bentonite, beneficiated hectorite, beneficiated bentonite, spray dried hectorite and mixtures thereof; and (b) one or more quaternary ammonium salts. 
     
     
       18. The process of claim 1, wherein the recovery step includes floatation of ink removed from the wastepaper to the surface of the aqueous system, and water washing of the deinked paper pulp.